- Equity Code :832537
Clinker grinding generates high-concentration, highly abrasive dust that demands a baghouse design engineered well beyond generic industrial standards. The core system comprises a filter housing, tube sheet, pulse-jet cleaning assembly, hopper, and rotary airlock. Filter bags are typically fabricated from woven fiberglass with PTFE membrane laminate or PPS needlefelt, both chosen for their resistance to abrasion and the moderate temperatures (80–130 °C) characteristic of finish grinding circuits.
The air-to-cloth ratio is the most consequential design parameter. For clinker dust with a bulk concentration often exceeding 50 g/m³ at the mill outlet, a gross filtration velocity of no more than 1.0–1.2 m/min is recommended to prevent premature bag blinding and maintain stable pressure drop. Compartmentalization—dividing the housing into multiple sections—allows individual rows to be taken offline for cleaning or inspection without interrupting continuous mill operation. Inlet duct geometry should incorporate anti-abrasion liners and distribute gas flow evenly across the tube sheet to avoid localized velocity peaks that accelerate bag wear.
Stable baghouse performance depends on maintaining three parameters within defined limits: differential pressure (ΔP), cleaning pulse pressure, and gas temperature at the inlet.
Under normal operation, ΔP across the filter media should remain between 1,000 and 1,500 Pa. A sustained rise above 1,800 Pa signals insufficient cleaning, blinded bags, or a tube sheet bypass; a sudden drop may indicate bag failure or a dislodged cage. Pulse-jet cleaning is typically set at 5–6 bar with an on/off timer sequence tuned to the mill's dust load—aggressive, frequent pulsing extends cleaning effectiveness but accelerates bag fatigue.
Integration with the grinding circuit requires careful coordination during mill start-up and shutdown. When the mill is idle, airflow should be reduced proportionally to prevent over-filtration velocity reversal and to avoid drawing cold ambient air below the dew point. Inlet gas temperature must be maintained at least 20–30 °C above the acid dew point—particularly relevant in mills handling clinker with residual sulfur compounds—to prevent moisture condensation that leads to bag blinding and corrosion of structural components.
A structured maintenance program is the most reliable driver of baghouse longevity and emission compliance. Key inspection intervals and tasks are outlined below.
Performance optimisation should be data-driven. Logging ΔP against production throughput over several months reveals whether rising resistance is due to increased clinker throughput, changing clinker mineralogy, or progressive bag blinding—each requiring a different corrective action. Where opacity exceedances correlate with specific process events (e.g., mill start-up, separator speed changes), targeted adjustments to cleaning frequency or inlet damper sequencing are usually more cost-effective than bag replacement.
